This policy is part of the Perl::Critic::Pulp add-on.
It asks you not to duplicate heading names in =head POD commands.

=head1 SOMETHING
=head1 SOMETHING # bad, duplicate

Duplication is usually a mistake, perhaps too much cut-and-paste, or a leftover from a template, or perhaps text in two places which ought to be together. On that basis this policy is under the "bugs" theme (see "POLICY THEMES" in Perl::Critic) and medium severity.

The policy default is to demand that a given heading is unique to its ancestors, siblings, and to the immediately adjacent heading irrespective of level. This is designed to be how human readers perceive the scope of headings and subheadings, plus adjacency in case a mixture of heading levels would let a duplicate otherwise go undetected. For example

Option uniqueness=all (see "CONFIGURATION" below) applies a stricter rule so that all =head names must be unique throughout the document, irrespective of levels and structure.

=head3 Foo
=head1 Bar
=head3 Foo # bad

One use for this is to ensure all headings can be reached by an L<> link. An L<> only has the heading name, no level or path, so if there's any duplication among the names then only the first of each duplicate will be reachable. (The POD browsers usually go to the first among duplicates.)

This rule is often too strict. It can be good to have similar subheadings like "Details" as shown above, with no need to make such sub-parts reachable by a link.

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